From: Dapeng Mi <dapeng1.mi@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
Eranian Stephane <eranian@google.com>,
Sandipan Das <sandipan.das@amd.com>,
Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
Ravi Bangoria <ravi.bangoria@amd.com>,
Ananth Narayan <ananth.narayan@amd.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
bpf@vger.kernel.org, Dapeng Mi <dapeng1.mi@intel.com>,
Zide Chen <zide.chen@intel.com>,
Falcon Thomas <thomas.falcon@intel.com>,
Xudong Hao <xudong.hao@intel.com>,
Dapeng Mi <dapeng1.mi@linux.intel.com>
Subject: [Patch v6 01/20] perf/x86: Disable LBR if x86_pmu.lbr_nr exceeds MAX_LBR_ENTRIES
Date: Fri, 6 Nov 2026 12:32:38 +0800 [thread overview]
Message-ID: <20261106043257.842864-2-dapeng1.mi@linux.intel.com> (raw)
In-Reply-To: <20261106043257.842864-1-dapeng1.mi@linux.intel.com>
Disable LBR if x86_pmu.lbr_nr is larger than MAX_LBR_ENTRIES, preventing
out-of-bounds access in the cached LBR stack handling path.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 4e344fb1ae3e..82d9b0e5ad1c 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2645,6 +2645,12 @@ static int __init init_hw_perf_events(void)
if (!x86_pmu.config_mask)
x86_pmu.config_mask = X86_RAW_EVENT_MASK;
+ if (x86_pmu.lbr_nr > MAX_LBR_ENTRIES) {
+ pr_warn("LBR entries %d exceeds max %d, disable LBR.\n",
+ x86_pmu.lbr_nr, MAX_LBR_ENTRIES);
+ x86_pmu.lbr_nr = 0;
+ }
+
perf_events_lapic_init();
register_nmi_handler(NMI_LOCAL, perf_event_nmi_handler, 0, "PMI");
--
2.34.1
next prev parent reply other threads:[~2026-11-06 4:40 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-06 4:32 [Patch v6 00/20] perf/x86: Fix multiple LBR sampling issues Dapeng Mi
2026-11-06 4:32 ` Dapeng Mi [this message]
2026-11-06 4:32 ` [Patch v6 02/20] perf/x86/intel: Validate LBR XSAVE state before updating LBR stack Dapeng Mi
2026-11-06 4:32 ` [Patch v6 03/20] perf/x86/amd/lbr: Limit branch snapshots to valid entries Dapeng Mi
2026-11-06 4:32 ` [Patch v6 04/20] perf/x86/intel/lbr: " Dapeng Mi
2026-11-06 4:32 ` [Patch v6 05/20] perf/x86: Add lbr_enabled to track LBR state Dapeng Mi
2026-11-06 4:32 ` [Patch v6 06/20] perf/x86/amd: Avoid re-enabling PMU and LBR for BPF when disabled Dapeng Mi
2026-11-06 4:32 ` [Patch v6 07/20] perf/x86/intel: Add helper to enable PMU without LBR Dapeng Mi
2026-11-06 4:32 ` [Patch v6 08/20] perf/x86/intel: Avoid re-enabling PMU and LBR for BPF when disabled Dapeng Mi
2026-11-06 4:32 ` [Patch v6 09/20] perf/x86/intel: Keep LBR frozen throughout PMI handling Dapeng Mi
2026-11-06 4:32 ` [Patch v6 10/20] perf: Add counted-bounds tracking for perf_branch_stack Dapeng Mi
2026-11-06 4:32 ` [Patch v6 11/20] perf/x86/intel: Allow LBR read helpers to operate on explicit stacks Dapeng Mi
2026-11-06 4:32 ` [Patch v6 12/20] perf/x86/intel: Use a dedicated LBR stack for BPF snapshotting Dapeng Mi
2026-11-06 4:32 ` [Patch v6 13/20] perf/x86/intel: Always snapshot live hardware LBR state for BPF Dapeng Mi
2026-11-06 4:32 ` [Patch v6 14/20] perf/x86/amd: Refresh LBR stack in PMI only when LBR users are active Dapeng Mi
2026-11-06 4:32 ` [Patch v6 15/20] perf/x86/intel: Refresh LBR stack for non-PEBS LBR events when needed Dapeng Mi
2026-11-06 4:32 ` [Patch v6 16/20] perf/x86/intel: Remove dead lbr_pebs_users Dapeng Mi
2026-11-06 4:32 ` [Patch v6 17/20] perf/x86/intel: Clear raw LBR counters in the LBR stack Dapeng Mi
2026-11-06 4:32 ` [Patch v6 18/20] perf/x86/intel: Refill LBR stack for LBR counter events in PMI handler Dapeng Mi
2026-11-06 4:32 ` [Patch v6 19/20] perf/x86/intel: Pass LBR stack size into store_lbr() Dapeng Mi
2026-11-06 4:32 ` [Patch v6 20/20] perf/core: Don't overwrite shared LBR stack depth Dapeng Mi
2026-11-06 7:23 ` [Patch v6 00/20] perf/x86: Fix multiple LBR sampling issues Mi, Dapeng
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